Abstract
Objective:
To determine the prevalence of dyslipidemia in HIV-infected patients using the first-line antiretroviral (ARV) drugs triple regimen.
Methods:
HIV-infected patients aged ≥15 years and attending Care and Treatment Clinic (CTC) at Muhimbili National Hospital, in Dar es Salaam, Tanzania, were recruited for the study. Blood samples from patients were collected during their regular visits at the CTC and assayed for determination of total cholesterol, triglycerides (TGs), high-density lipoprotein, low-density lipoprotein cholesterol, and CD4 counts.
Results:
The median CD4 count was 346 cells/mm3 (2-2600). Triple therapy combinations of ARV drugs used by patients included zidovudine (ZDV)/lamivudine (3TC)/efavirenz (EFV; 42.4%), ZDV/3TC/nevirapine (NVP; 33.8%), tenofovir (TDF)/emtricitabine/EFV (19.9%), and TDF/3TC/EFV (3.9%). The overall prevalence of dyslipidemia in patients was 77.5%. There were varied prevalence of derangement of individual lipids among patients. Age, body mass index, CD4 count, sex, and duration of ARV drug use were the predictors of poor lipid profiles.
Conclusion:
The findings of this study indicate the need for routine monitoring of lipids among HIV-infected patients.
Keywords
Introduction
About 5.1% of Tanzanians aged 15 to 49 years are infected with HIV. The prevalence of HIV is higher among women (6.2%) than men (3.8%). However, the introduction of highly active antiretroviral therapy (HAART), a combination of at least 3 drugs that typically includes either a protease inhibitor (PI) or a nonnucleoside reverse transcriptase inhibitor (NNRTI) and 2 nucleoside reverse transcriptase inhibitors (NRTIs), has rapidly decreased HIV-linked mortality and morbidity. 1 –4 Life expectancy has increased considerably as a result of antiretroviral therapy (ART), but cardiovascular disease has emerged as an important concern due to the use of these drugs. 5
Dyslipidemia is a common problem affecting HIV-infected patients receiving ARV drugs. 6 –8 It is a primary major risk factor for cardiovascular diseases and may even be a prerequisite for cardiovascular disease, occurring before other major risk factors come into play. Its development involves multiple factors among which are those directly related to ARV drugs, inflammation, hormonal, and other genetic factors. Improved health status and health restoration may also play a role in ART-related lipid disturbances. 7,9
Cardiovascular manifestations of HIV have been altered by the introduction of HAART regimens. On one hand, HAART has significantly modified the course of HIV disease, prolonged survival, and improved the quality of life of HIV-infected patients. On the other hand, reports have suggested that HAART is associated with an increase in both peripheral and coronary arterial diseases. 10,11 Earlier trials of lipid-lowering drugs in the primary prevention of coronary heart disease have demonstrated that lowering the cholesterol levels in middle-aged men with hypercholesterolemia reduces the incidence of myocardial infarction. 10,12
The etiology of coronary heart disease is multifactorial. Among other factors, high levels of low-density lipoprotein (LDL) cholesterol (LDL-C) and low levels of high-density lipoprotein (HDL) cholesterol (HDL-C) have been identified as risk factors for coronary heart disease in the general population. 13,14 The importance of lipid disorders in patients with HIV infection is based on the increased cardiovascular risk associated with ART. Current trends suggest an increase in cardiovascular diseases in HIV-infected patients due to aging and increased survival, so that the control of modifiable risk factors such as dyslipidemia should be a priority in the clinical management of HIV-infected patients. 12,15 –18
Dyslipidemia, as a risk factor for cardiovascular diseases, is manifested by elevation or attenuation of plasma concentration of lipoproteins. Several methods have been used to classify lipoproteins with respect to their density, physical, and chemical properties. Based on these classifications, different types of lipoproteins, including chylomicrones, intermediate density lipoprotein 1, very LDL (VLDL) 2, LDL3, and HDL4, and apolipoproteins (apo), including apo A, apo B, apo C, and apo E, have been introduced. Generally, dyslipidemia is defined as the total cholesterol (TC), LDL, triglycerides (TGs), apo B or lipoprotein(a) levels above the 90th percentile or HDL and apo A levels below the 10th percentile of the general population. 19
A study by Mgunya at Muhimbili National Hospital (MNH) in Tanzania showed that the use of ARV drugs was significantly associated with increased levels of TC, TGs, LDL, impaired fasting blood glucose, and diabetic mellitus. 17 However, that study included patients who were on both the first-line and second-line ARV regimens. In this study, we assessed patients who were using the first-line ARV regimens only. Also in the study by Mgunya, only patients aged ≥30 years were evaluated. Therefore, there are no data of lipid profiles for patients of younger age (<30 years) who are using the first-line ARV drugs in Tanzania.
Methods
Study Design and Setting
This was a cross-sectional and hospital-based study. HIV-infected patients who were attending Care and Treatment Clinic (CTC) at the MNH in Dar es Salaam were recruited in the study. The MNH is the largest public and tertiary-level referral hospital in Tanzania. It treats patients referred from district hospitals and from neighboring regions. It is located in the city of Dar es salaam, which is also the largest commercial city in the country with a population of about 4 million. The MNH referrals are mainly those patients who are diagnosed to have HIV while admitted in the wards. Patients attend the clinic once in a month for clinical evaluation and prescription refill for ARV drugs. Currently, there are about 6500 HIV-infected outpatients receiving ART at the CTC. On average, there are about 60 HIV-infected patients attending CTC at MNH for ARV drug prescription refill and clinical assessment per day.
Study Population
This study was conducted for 3 months from January 2014 to end of March 2014. A total of 230 patients were recruited into the study using systematic sampling. These were HIV-infected patients who were using ARV drugs triple combination therapy for ≥24 weeks. The reason for selecting this duration of time for ARV drug use is based on the fact that by this time, the effect of ARV drugs on serum lipid profile is established. 20 The target patients were those at the age of ≥15 years attending CTC at MNH. Critically ill patients, patients receiving anabolic steroids, corticosteroids, immune-modulating therapy, anti-dyslipidemic drugs, and second-line ARV drugs were excluded from the study.
Data Collection
Data collected included sociodemographic characteristics, clinical data (AIDS events and known risk factors for cardiovascular diseases), laboratory markers (CD4 counts, LDL-C, TC, HDL-C, and TG levels), and ART. The history of ART and HIV infection was recorded from patient’s CTC card 1 (CTC1) or CTC card 2 (CTC2).
Blood Sample and Assay
Blood samples were collected from the study participants in the morning hours under fasting condition. Blood samples in vacutainer tubes were then coded, labeled, and taken to MNH laboratory for assay. For analysis of TC, TG, HDL, and LDL levels, blood samples were collected from patients into collecting tubes (serum and plasma tubes) and then cooled. The cooled specimens were then centrifuged at 10 000 relative centrifugal force (RCF) for 10 minutes. The centrifuged specimens with lipid layer on top were then transferred into secondary tubes in the architect clinical chemistry analyzer for lipid profiling. 21 CD4 counts were recorded from CTC1 or CTC2 cards for patients whose CD4 counts for the previous 6 months were available. For those whose data were not available, CD4 count was assayed. Blood samples were drawn from patients into vacutainer tubes with ethylenediaminetetraacetic acid (EDTA). CD4 counts were assayed by flow cytometry using Becton Dickson FacsCalibur machine (BD Biosciences, San Jose, CA, USA) as previously described. 22
Demographic Information
Sociodemographic data included age, sex, height, weight, and body mass index (BMI) of patients. Weight was measured by using a seca scale, with the patient on bare feet. Weight was measured up to the nearest 100 g. Height was measured using a standard height board with the participants on bare feet. Body mass index was calculated as weight in kilograms divided by height in meter square.
Operational Definitions
Concentrations of serum lipids were graded according to the criteria established by the American Association of Clinical Endocrinologists. 23 Atherogenic dyslipidemia manifests in routine lipoprotein analysis and is defined as the presence of any of the following lipid abnormalities: hypercholesterolemia, hypertriglyceridemia, low HDL-C, or increased LDL-C. All of these abnormalities have been implicated as being independently atherogenic. 23,24 In this study, hypercholesterolemia was defined as total serum cholesterol of >5.17 mmol/L. Hypertriglyceridemia was defined as serum TG of > 1.69 mmol/L, decreased HDL was defined as serum HDL levels of <1.04 mmol/L, and increased LDL was considered as serum LDL levels of >3.3 mmol/L. 17,23 Patient’s BMI were categorized as underweight (<18.5 kg/m2), normal (18.5-25 kg/m2), overweight (25-29 kg/m2), and obese (≥30 kg/m2). 25
Statistical Analysis
The outcomes of interest in this study were lipid parameters (TC, TG, HDL-C, and LDL-C). Predictor risk factors for dyslipidemia were age, sex, CD4 count, ARV regimen, duration of ART use, and presence of comorbidity among patients. Summary statistics were presented as proportions for categorical variables and as means (standard deviations) or medians (interquartile range) for continuous variables. Pearson chi-square analysis was used to examine the differences in the proportions of abnormal lipid parameters between the various categories of an explanatory variable. The relationships between the dependent variables (TC, HDL-C, LDL-C, and TG levels) and treatment groups were studied by the use of multiple logistic regression models. Associations were considered to be statistically significant at a P value of ≤.05. All factors with P value of ≤0.2 on univariate analysis were considered for multivariate binary logistic regression analysis so as to control for confounding factors. All statistical analyses were performed by using Statistical Package for Social Sciences computer software version 20.
Ethical Considerations
Ethical clearance was sought from Muhimbili University of Health and Allied Sciences Research and Publications Committee. Permission to collect data was also sought from the management of MNH. Written informed consent was obtained from patients. All the information provided was kept confidential and no unauthorized persons had access to the data collected. Each study participant was assigned a study identification number, and these identifiers were not released outside the research group. Codes were used and no identification was made for the responders.
Results
Patients Characteristics
The study included 231 patients who were receiving ART at the CTC between January 2014 and March 2014. These were patients who were attending the clinic for their routine prescription refill and monitoring. Majority of patients (76.2%) were females. The mean age of the patients was 42 ± 9.19 years, ranging from 15 to 70 years. The mean BMI of patients was 26 ± 5.8 kg/m2, and the median CD4 lymphocyte count was 364 (2-2600) cells/mm3 (Table 1).
Sociodemographic and Clinical Characteristics of Study Participants.a
Abbreviations: ARV, antiretroviral; EFV, efavirenz; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; NVP, nevirapine; TC, total cholesterol; TDF, tenofovir; TG, triglyceride; ZDV, zidovudine; 3TC, lamivudine.
aN = 231.
The duration from the date of initiation of ART among patients ranged from 6 to 287 months with a median of 24 months. The first-line ARV regimens were a combination of 2 NRTIs and 1 NNRTIs.
The NRTIs consisted of zidovudine (ZDV) and tenofovir (TDF), with lamivudine (3TC) constantly present in 3 of the first-line triple combination antiretroviral (ARV) regimens. Zidovudine was the NRTI backbone in 176 (76.2%) cases, while efavirenz (EFV) was used by 153 (66.2%) patients as the preferred NNRTI. Ninety-eight (42.4%) patients were using a combination of ZDV, 3TC, and EFV (ZDV/3TC/EFV), while 78 (33.8%) patients were using ZDV, 3TC, and NVP (ZDV/3TC/NVP). The remaining 55 (23.8%) patients were using TDF-based regimens. Of these, 46 (19.9%) patients were using TDF, emtricitabine, and EFV (TDF/FTC/EFV), and 9 (3.9%) patients were on TDF, 3TC, and EFV (TDF/3TC/EFV; Table 1).
Prevalence of Dyslipidemia among Patients
Figure 1 shows lipid profiles of HIV-infected patients who were using ARV drugs. Dyslipidemia was detected in 179 (77.5%) patients. Increased LDL-C was the most prevalent (59.8%), with no significant differences between males and females (P = .293). The prevalence of hypercholesterolemia, hypertriglyceridemia, low HDL, and increased LDL was 53.5%, 29.6%, 16.5%, and 59.8%, respectively.

Prevalence of dyslipidemia in HIV-infected patients using first-line antiretroviral drugs.
All factors with P value of ≤0.2 on univariate analysis were considered for multivariate binary logistic regression analysis in order to control for confounding factors. Table 2 shows the factors associated with dyslipidemia on binary logistic regression analysis. In this analysis, age, normal BMI, overweight, obesity, CD4 counts, sex, and duration of ARV drug use were found to be predictors of poor lipid profiles. The types of ARV regimen used did not show statistically significant association with dyslipidemia (Table 2).
Association of Dyslipidemia with Patient-Related Factors among Patients using the First-Line Antiretroviral Drugs.a
Abbreviations: ARV, antiretroviral; BMI, body mass index; CI, confidence interval; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; NNRTI, nonnucleoside reverse transcriptase inhibitor; NRTI, nucleoside reverse transcriptase inhibitor; OR, odds ratio; TC, total cholesterol; TG, triglyceride.
aN = 231.
Hypercholesterolemia
In multivariable logistic regression analysis, there was evidence that patients who were using ARV drugs for more than 2 years were 3.46 times more likely to have hypercholesterolemia (adjusted odds ratio [aOR] = 3.46, 95% confidence interval [CI]: 1.45- 8.274, P = .005) than those who were using ARV drugs for less than a year. On the other hand, patients with normal BMI were about 3 times less likely than obese patients to have hypercholesterolemia (aOR = 0.38, 95% CI: 0.179-0.801, P = .011). Patients who were ≥50 years were 8.46 times more likely to have hypercholesterolemia (aOR 8.46, CI 2.329-30.711, P = .001) as compared to younger patients in the age-group of 15 to 30 years.
Hypertriglyceridemia
Patients who had CD4 counts of <350 cells/mm3 were 2.3 times less likely than those with CD4 counts of >500 cells/mm3to have hypertriglyceridemia (aOR 0.43, CI: 0.21 -0.897, P = .024). Patients with CD4 counts of 350 to 500 cells/mm3 were about 2.8 times less likely than those who had CD4 counts of >500 cells/mm3 to have hypertriglyceridemia (aOR = 0.35, 95% CI: 0.137-0.892, P = .024). Patients who were using ARV drugs for 12 to 24 months were 4 times more likely to develop hypertriglyceridemia (aOR = 4.01, 95% CI: 1.03-15.621, P = .045) as compared to those who were using the same regimen for less than a year. On the other hand, patients who were using ARV drugs for more than 2 years were 4.42 times more likely to develop hypertriglyceridemia (aOR 4.42, 95% CI: 1.178-16.549, P = .028). Moreover, patients with normal BMI were 2.4 less likely than obese patients to have hypertriglyceridemia (aOR = 0.41, 95% CI: 0.186-0.925, P = .032).
Derangement of HDL-C
Male patients were 2 times more likely to have decreased HDL-C (aOR = 2.15, 95% CI: 1.021-4.521, P = .044) as compared to females. Patients who were using ARV drugs for 12 to 24 months were 2.9 times less likely to develop elevated LDL-C (aOR = 0.347, 95% CI: 0.18-0.67, P = .002) as compared to those who were using the same regimen for more than 2 years. Obese patients were 3.43 times more likely than underweight patients to have elevated LDL-C (aOR 3.43, 95% CI: 1.101-10.706, P = .034). With respect to age, patients who were ≥50 years were 5 times more likely younger patients in the age-group of 15 to 30 years to have elevated LDL-C (aOR 8.46, 95% CI: 2.33-30.71, P = .001; Table 2).
Discussion
In this study, we report a high prevalence of dyslipidemia in HIV-infected patients using the first-line ARV drugs. Patients who were using ARV drugs for more than 2 years were significantly associated with lipid derangement as compared to those who were using ARV drugs for less than a year. This is probably related to a combination of the effects of an aging HIV-infected population coupled with improved health due to suppression of viral load and the effect of ARV drugs on lipid metabolism. The results in this study are comparable to those of the previous studies, indicating that duration of ARV drug use is positively associated with the prevalence of dyslipidemia. 26 For instance, a study conducted in rural Uganda indicated that the mean TC, LDL-C, and HDL-C levels were significantly higher at 24 months than at baseline. 26
Other studies conducted in Europe, United States, and Cameroon showed that being on ARV drugs for more than 2 years was associated with poor lipid profiles. 27,28 The latter were follow-up studies in which it was seen that the duration on ARV drug use was associated with a cardioprotective lipid profile in the short term, because after initiation of ART, lipid levels return to baseline levels, but soon they rise above preseroconversion levels in the long term. 26,28,29 These findings suggest that dyslipidemia develops with cumulative duration of exposure to ARV drugs.
Hypercholesterolemia, hypertriglyceridemia, low HDL-C, and increased LDL-C were the most common forms of dyslipidemia in this study. Of these, elevated LDL-C is most closely linked to cardiovascular risks and usually is the primary target of therapeutic interventions. High TG levels in HIV-infected patients have been postulated to be due to inflammation with subsequent cytokines release and decreased hepatic clearance related to a role of apolipoprotein. 30 Estrogen treatment can aggravate hypertriglyceridemia by increasing VLDL secretion and reducing hepatic TG lipase activity. 31 From these findings, it was expected that women would have had high TG levels. However, the results of this study show that males had much higher prevalence of hypertriglyceridemia than females. This observation is in line with the findings of the study by Ervin 32 in the United States in which the prevalence of hypertriglyceridemia was found to be higher in males than females.
The prevalence of hypertriglyceridemia in our study is however slightly lower compared to 36.4%, which was reported by Mgunya. 17 The reason for this difference could be due to the fact that the later study included patients who were using both the first-line and PI-containing ARV drugs. The prevalence of hypertriglyceridemia in the present study is also much lower than that reported by Bekolo et al 27 (51.8%) in rural Cameroonia population, and in a study by Pefura et al (43.5%), which included both ARV-drug-experienced and ARV-drug-naive patients in urban Cameroonian population. 33
High-density lipoprotein cholesterol is positively associated with a decreased risk of cardiovascular diseases. As defined by the US National Cholesterol Education Program Adult Treatment Panel III guidelines, an HDL-C of ≥60 mg/dL is a negative (protective) risk factor. 34 In our study, there were no significant differences in the prevalence of lipid abnormalities in patients on regimens that included ZDV as compared with those using TDF. The prevalence of lipid abnormalities induced by NVP and EFV was also similar. This is in contrast with the previous reports where patients taking NVP-based regimen were found to have higher levels of HDL-C as compared to patients who were using EFV-based regimen. 20,35 In a study by van Leth et al, 35 HIV-infected patients were given stavudine (d4T) and 3TC with either NVP or EFV. In that study, patients taking NVP-based regimen were reported to have higher levels of HDL-C as compared to patients who were using EFV-based regimen. 35 These observed differences between the findings of our study and the later study could be due to the fact that the later was a follow-up study and also included d4T and 3TC as NRTI backbone with either EFV or NVP. The inclusion of d4T in the later study could be the main cause of increased serum lipid levels. 2,36 In the current study, the nucleoside backbone used in the first-line ARV drugs was either ZDV or TDF.
In terms of the relationship between poor lipid profile and immune status of the patients, we observed that there was a trend of increasing prevalence of dyslipidemia toward increasing CD4 counts. This is probably due to the fact that the use of ARV drugs leads to suppression of viral load, resulting in increased CD4 count. This allows immune recovery leading to elevation of lipids in addition to the continued effect of ARV drugs in elevating lipid levels. As it has been reported in a study by Pefura et al 33 in Cameroon, ART-experienced patients are more likely to have high CD4 count and high BMI, indicating immune recovery and health restoration. However, patients with low CD4 counts also experienced poor lipid profile, indicating that low CD4 counts are associated with high viral load. Alterations in cholesterol metabolism that occur in HIV-infected patients could be explained by lipid peroxidation. The cytokine tumor necrosis factor plays a role in plasma lipoprotein peroxidation in HIV-infected patients by stimulating the production of reactive oxygen species. This is in agreement with earlier reports indicating that dyslipidemia in HIV-infected patients is partly due to the effect of the HIV itself on lipid metabolism. 7,9,37
Levels of lipoproteins and therefore lipids, particularly LDL-C, increase slightly as people age. 9,38,39 Levels are normally slightly higher in men than in women, but lipoproteins increase mostly in women after menopause. The increase in levels of lipoproteins that occurs with age can result in dyslipidemia and increase the risk of atherosclerosis. In our study, the prevalence of dyslipidemia increased significantly with advanced age. The findings of the current study shows similar trend as the previous report by Wang et al 40 in the general population in rural and urban China. However, the study participants in the later study had very low prevalence of dyslipidemia compared to the prevalence of dyslipidemia in the current study. This could explain the additional effect of HIV itself and ARV drugs on lipid metabolism in the current study. On the other hand, males in this study had higher overall prevalence of dyslipidemia as compared to females, indicating protective effect of estrogen in premenopausal women. 38,40
Conclusion
Overall, the findings from the current study indicate that there was high prevalence of dyslipidemia among HIV-infected patients using first-line ARV drugs. Dyslipidemia among patients taking ARV drugs is related to multiple factors, including individual patient characteristics, HIV infection itself, and use of ARV drugs. The use of first-line ARV drugs was associated with a lipid profile that is likely to increase the risk of cardiovascular disease. Therefore, these findings indicate the need to assess lipid profiles at baseline before initiation of ART and monitoring the same during therapy. Our study was cross-sectional and inference about causal relationship could not be made. Cohorts’ studies would be appropriate to monitor lipid profile alterations in patients using first-line ARV drugs and their potential impact on cardiovascular health of people living with HIV in our settings.
Footnotes
Declaration of Conflicting Interests
The author(s) declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors received financial support for the research from the Ministry of Health and Social Welfare in Tanzania.
